President Obama's trip through Africa is turning out to be political and also personal. The Obama family is visiting three countries in vastly different regions of the continent.

Today, they fly from the West African nation of Senegal to South Africa, where the beloved anti-apartheid leader Nelson Mandela remains hospitalized in critical condition. Nobody knows for sure yet whether the two men will meet on this visit.

But as NPR's Ari Shapiro reports from Senegal, Mandela was a main focus of the president's press conference yesterday.

ARI SHAPIRO, BYLINE: The last time Barack Obama and Nelson Mandela saw each other was briefly in 2005 when Obama was a senator. But Obama says Mandela's influence on him stretches back much farther than that.

PRESIDENT BARACK OBAMA: He's a personal hero, but I don't think I'm unique in that regard. I think he's a hero for the world.

SHAPIRO: At a news conference in Dakar, Obama reminisced about his first experience with political activism, working against apartheid as a college student. And he described his wonder as a law student when he saw Mandela step free, only to embrace his former captors and work for peace.

OBAMA: It gave me a sense of what is possible in the world when righteous people, when people of goodwill, work together on behalf of a larger cause.

SHAPIRO: That theme came up repeatedly yesterday. Obama told a group of African judges that it's their responsibility to stand up for the defenseless. He praised a group of civil society leaders for supporting the voiceless. And on Goree Island, Obama walked in the steps of the powerless.

UNIDENTIFIED MAN: So that white slave house was one of the last to be built on the island of Goree.

SHAPIRO: A tour guide showed the Obama family through the slave house, a small two-story building where thousands of Africans were crammed into dark rooms before being shipped across the Atlantic.

Obama peered out to sea through the Door of No Return. Then he stepped back onto the dusty path and described what visiting this place means to him.

OBAMA: Obviously, for an African-American, an African-American president, you know, to be able to visit this site, I think gives me even greater motivation in terms of the defense of human rights around the world.

SHAPIRO: As he walked back to the port to catch the ferry to the mainland, crowds of people thronged the walkway, singing songs about Obama.

(SOUNDBITE OF SINGING AND CLAPPING)

UNIDENTIFIED PEOPLE: (Singing in Foreign Language)

SHAPIRO: Kids wore T-shirts with Obama's face that said, Welcome Home. This is Obama first major trip as president through a continent where many consider him one of their own.

Yet as president, he's been much less engaged in Africa than his two immediate predecessors, both of whom spearheaded major aid programs to the continent.

At the presidential palace in Dakar, Obama said it's time for a change.

OBAMA: Yeah, what I want us to do is to have a shift in paradigm where we start focusing on trade, development, partnerships, where we see ourselves as benefiting and not simply giving in the relationship with Africa.

SHAPIRO: At this press conference, Obama also spoke about the domestic news of the day. He described the Supreme Court's same-sex marriage ruling this way.

OBAMA: Not simply a victory for the LGBT community, I think it was a victory for American democracy.

SHAPIRO: He said his team is now trying to figure out how to apply that ruling across a patchwork of state laws. And he was harshly critical of this week's other major Supreme Court ruling. The court struck down part of the Voting Rights Act, a law the president described this way.

OBAMA: It was the cornerstone and the culmination of years of struggle. Blood, sweat, tears, in some cases deaths.

SHAPIRO: That struggle for equality will continue to be a major theme of this trip - as President Obama flies to South Africa today, a place that has gone through its own share of bloodshed on the path to democracy.